1. Field of the Invention
The present invention is directed generally to an overpressure break-away fuse in an electrical capacitor, and more particularly to an overpressure break-away fuse composed of a break-away element having a rated break location arranged essentially symmetrically relative to a longitudinal axis of the break-away element. The invention is particularly adapted for use in power capacitors.
2. Description of the Related Art
A capacitor is disclosed in German Patent 975,024 and the corresponding U.S. Pat. No. 2,896,049. The capacitor includes a break-away element composed of a break-away strip of metal inserted between two tension members. The break-away strip has a rated break location arranged essentially symmetrically relative to its longitudinal axis. The rated break location is composed of two punched notches lying opposite one another in the strip.
German Published Application 30 47 876 A1 discloses a break-away wire for an overpressure break-away fuse that is provided with a rated break location having a diminished cross section that is punched in, whereby the punched part of the wire is preserved during the process so that the punched portion of the wire remains on the wire offset after it is punched.
Further, German Patent No. 22 20 022 C3 discloses a break-away wire having a rated break location of reduced cross section, whereby the wire material is mechanically eroded at one side eccentrically relative to the wire axis.
Due to the manufacturing processes used, the geometries of the known rated break locations for electrical capacitors exhibit sharp edges and/or points that lead to a disturbance of the electrical and magnetic fields therein. As a result, disturbing effects appear which have an undesirable effect on the current flow, which in turn leads to localized heating and a greater tendency toward sparking.